Color active matrix type vertically aligned mode liquid crystal display and driving method thereof

ABSTRACT

A big screen display suitable for moving image displaying that has an excellent viewing angle property, an excellent reliability and a productivity, and a quick speed of response, and has a bright and excellent contrast is realized at low cost. Vertically aligned mode liquid crystal display comprises a scan wiring, a video signal wiring, a pixel electrode, an alignment directional control electrode, and a thin film transistor element formed in a position where a scan wiring and a video signal wiring intersect with each other, and a common electrode formed in opposing substrate side. An electric field distribution formed with three electrodes comprising an alignment directional control electrode, and a pixel electrode, and a common electrode formed in an countering substrate side may control motion directions of vertically aligned anisotropic liquid crystal molecules having a negative dielectric constant.

FIELD OF THE INVENTION

The present invention relates to a big screen active matrix type liquidcrystal TV viewing display, and more particularly, to an active matrixtype liquid crystal display having a wide viewing angle, highbrightness, and a high response speed as well as low cost, and to amethod for driving the display.

BACKGROUND OF THE INVENTION

As shown in FIG. 1, in conventional type vertically aligned mode liquidcrystal displays, a mode is adopted in which bumps 5 for controlling amotion direction of liquid crystal molecules 14 are formed on atransparent common electrode 4 of a color filter side substrate 1, andslits 9 for controlling a motion direction of the liquid crystalmolecules 14 are provided in transparent pixel electrodes 8 of an activematrix substrate 13, the bumps 5 and the slits 9 determine the motiondirection of the liquid crystal molecules 14 serving as one set. Thereis also provided a method in which slits for controlling the motiondirection of the liquid crystal molecules 14 in place of bumps 5 areformed on a transparent common electrode 4 on the color filter sidesubstrate 1. Both of these modes are put in practical use formass-production.

In conventional type multi-domain vertically aligned mode liquid crystaldisplays, it is necessary that bumps or slits are formed on thetransparent common electrode in the color filter side substrate, whichrequired one excessive photo mask process. Therefore, in thisconventional technology, cost increase is unavoidable.

Moreover, in vertically aligned mode liquid crystal displays with bumps5 formed in the color filter layer 3 side, as shown in FIG. 1, when awidth, a pitch, and an angle of the slope of the bumps 5 are notprecisely controlled, variation in the tilting degree of liquid crystalmolecules 14 is occurred, which frequently causes unevenness in halftone area.

Since bumps are made of positive type photoresists, perfect removal oforganic solvents, and furthermore hardening by baking at hightemperatures of no less than 200 degrees are furthermore required,leading difficulty in shortening the processes. When contaminants areeluted out into liquid crystals from the bumps of positive typephotoresists, a phenomenon of afterimage will occur, resulting inreliability problems.

In color filter substrates using the conventional bumps, positive typephotoresists are used as materials for the bumps, and therefore, when adefect occurs in the application process of a vertical alignment film 6and reworking is required, a dry ashing method using oxygen plasma cannot be used. Therefore, a wet remove method requiring high running costusing organic solvents has to be used, which causes a disadvantagerequiring a very high reworking cost.

In vertically aligned mode liquid crystal displays using theconventional type bumps and slits, when a display switchovers to a halftone display from a black display, or to a half tone display from awhite display, there arises defects that the liquid crystals operate ina slow response speed.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above-mentionedproblems, and it is an object of the present invention to improvereliability of a large-sized vertically aligned mode liquid crystaldisplay.

It is also an object of the present invention to provide a large-sizedvertically aligned mode liquid crystal display that can be manufacturedat low cost in a short time, while having capability of high brightnessand high response speed.

In order to solve the problems in the conventional technology and toachieve the above-mentioned objects, following methods are used in thepresent invention.

[Method 1]

In order to impress a voltage to anisotropic liquid crystal moleculesthat are vertically aligned to an active matrix substrate and a colorfilter substrate and have a negative dielectric constant, and to makethe liquid crystal molecules tilt in different two directions or fourdirections, two kinds of following electrode structures were formed inone pixel of the active matrix substrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns (no transparent electrode in a slit part) having a shape of along and slender slit are formed.ii) a transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, two rowsof liquid crystal alignment direction control electrodes that aremutually separated and set as potentials different from each other existin a lower layer of the transparent pixel electrode via an insulatedfilm, either of the liquid crystal alignment direction controlelectrodes have almost the same shape as a shape of a pattern of theshape of long and slender slits, and a larger dimension than a dimensionof the slit; and two rows of the liquid crystal alignment directioncontrol electrodes mutually separated are arranged in a direction of ascan signal wire in a lower layer of the long and slender slits that areformed, mutually exchanged in an every fixed pixel cycle, in thetransparent pixel electrode.[Method 2]

A following drive system is used as a method for driving the verticallyaligned mode liquid crystal display having the electrode structure bythe method 1.

There is used a drive system in which: when a potential of thetransparent pixel electrode separated for every pixel of an activematrix substrate side is lower than a potential of the countering flatcommon electrode on a color filter substrate side, a potential of theliquid crystal alignment direction control electrode currently placed ina lower layer of the slit of the transparent pixel electrode is setlower than a potential of the transparent pixel electrode; and when apotential of the transparent pixel electrode is higher than a potentialof the countering flat common electrode of the color filter substrateside, a potential of the liquid crystal alignment direction controlelectrode placed in a lower layer of the slit of the transparent pixelelectrode is set higher than a potential of the transparent pixelelectrode, and potentials of the liquid crystal alignment directioncontrol electrodes arranged in the vicinity of both sides of the scansignal wiring are set as polar potentials different from each other, andpolarities of the potential of the transparent pixel electrode, and eachof the potential of the two rows of the liquid crystal alignmentdirection control electrodes mutually separated in one pixel arereversed to a polarity of a polarity of the potential of the flat commonelectrode in a color filter substrate side every vertical scanningperiod.

[Method 3]

In a color active matrix type vertically aligned mode liquid crystaldisplay in which adjacent transparent pixel electrodes in a direction ofa scan signal wiring are connected to a thin film transistor componentcontrolled by mutually different scan signal wirings, in order toimpress a voltage to liquid crystal molecules that are verticallyaligned between an active matrix substrate and a color filter substrateand to make the liquid crystal molecules tilt in different twodirections or different four directions, two kinds of followingelectrode structures were formed in one pixel of the active matrixsubstrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns (no transparent electrode in a slit part) having a shape of along and slender slit are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, and aliquid crystal alignment direction control electrode having almost thesame shape as a shape of the slit, and a larger dimension than adimension of the slit are formed in a lower layer of the slit via aninsulated film.[Method 4]

A following drive system is used as a method for driving the verticallyaligned mode liquid crystal display having the electrode structure bythe method 3.

There is used a drive system in which: when a potential of thetransparent pixel electrode separated for every pixel of an activematrix substrate side is lower than a potential of the countering flatcommon electrode on a color filter substrate side, a potential of theliquid crystal alignment direction control electrode currently placed ina lower layer of the slit of the transparent pixel electrode is setlower than a potential of the transparent pixel electrode; and when apotential of the transparent pixel electrode is higher than a potentialof the countering flat common electrode of the color filter substrateside, a potential of the liquid crystal alignment direction controlelectrode placed in a lower layer of the slit of the transparent pixelelectrode is set higher than a potential of the transparent pixelelectrode; and polarities of the potential of the transparent pixelelectrode, and of the potential of the liquid crystal alignmentdirection control electrode are reversed to a polarity of a potential ofthe flat common electrode in a color filter substrate side everyvertical scanning period.

[Method 5]

In order to impress a voltage to anisotropic liquid crystal moleculesthat are vertically aligned to an active matrix substrate and a colorfilter substrate and have a negative dielectric constant, and to makethe liquid crystal molecules tilt in many directions, two kinds offollowing electrode structures were formed in one pixel of the activematrix substrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode on the active matrix substrate side,many circular or polygonal holes (no transparent electrodes in a portionof a hole) are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, two rowsof liquid crystal alignment direction control electrodes that aremutually separated and set as potentials different from each other existin a lower layer of the transparent pixel electrode via an insulatedfilm, either of the liquid crystal alignment direction controlelectrodes has almost the same shape as a shape of a pattern of theshape of long and slender slits, and a larger dimension than a dimensionof the slit, and two rows of the liquid crystal alignment directioncontrol electrodes mutually separated are arranged in a direction of ascan signal wiring in a lower layer of the long and slender slits thatare formed, mutually exchanged in an every fixed pixel cycle, in thetransparent pixel electrode.[Method 6]

A following drive system is used as a method for driving the verticallyaligned mode liquid crystal display having the electrode structure bythe method 5.

There is used a drive system in which: when a potential of thetransparent pixel electrode separated for every pixel of an activematrix substrate side is lower than a potential of the countering flatcommon electrode on a color filter substrate side, a potential of theliquid crystal alignment direction control electrode currently placed ina lower layer of a slit of the transparent pixel electrode is set lowerthan a potential of the transparent pixel electrode; and when apotential of the transparent pixel electrode is higher than a potentialof the countering flat common electrode of the color filter substrateside, a potential of the liquid crystal alignment direction controlelectrode placed in a lower layer of the slit of the transparent pixelelectrode is set higher than a potential of the transparent pixelelectrode; and potentials of the liquid crystal alignment directioncontrol electrodes arranged in the vicinity of both sides of the scansignal wiring are set as polar potentials different from each other, andpolarities of the potential of the transparent pixel electrode, and ofeach of the potential of the two rows of the liquid crystal alignmentdirection control electrodes mutually separated in one pixel arereversed to a polarity of a potential of the flat common electrode in acolor filter substrate side every vertical scanning period.

[Method 7]

In an active matrix type vertically aligned mode liquid crystal displayin which adjacent transparent pixel electrodes in a direction of a scansignal wiring are connected to a thin film transistor componentcontrolled by mutually different scan signal wirings, in order toimpress a voltage to liquid crystal molecules that are verticallyaligned between an active matrix substrate and a color filter substrateand to make the liquid crystal molecules tilt in many directions, twokinds of following electrode structures were formed in one pixel of theactive matrix substrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,many circular or polygonal holes (no transparent electrodes in a portionof a hole) are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, a liquidcrystal alignment direction control electrode having almost the sameshape as a shape of the slit, and a larger dimension than a dimension ofthe slit are formed in a lower layer of the slit via an insulated film.[Method 8]

A following drive system is used as a method for driving the verticallyaligned mode liquid crystal display having the electrode structure bythe method 7.

There is used a drive system in which: when a potential of thetransparent pixel electrode separated for every pixel on an activematrix substrate side is lower than a potential of the countering flatcommon electrode on a color filter substrate side, a potential of theliquid crystal alignment direction control electrode currently placed ina lower layer of a slit of the transparent pixel electrode is set lowerthan a potential of the transparent pixel electrode; and when apotential of the transparent pixel electrode is higher than a potentialof the countering flat common electrode of the color filter substrateside, a potential of the liquid crystal alignment direction controlelectrode placed in a lower layer of the slit of the transparent pixelelectrode is set higher than a potential of the transparent pixelelectrode; and polarities of the potential of the transparent pixelelectrode, and of the potential of the liquid crystal alignmentdirection control electrode are reversed to a polarity of a potential ofthe flat common electrode in a color filter substrate side everyvertical scanning period.

[Method 9]

In the method 1 and 3, the slit formed in the transparent pixelelectrode in an active matrix substrate side and extending long andslender, and the slit forming a group with the liquid crystal alignmentdirection control electrode are arranged alternately, maintaining analmost parallel relationship in a direction making about ±45 degrees toa direction of the scan signal wiring; and polarization axes of twopolarizing plates placed in exterior of a liquid crystal cell arearranged in a direction of the scan signal wiring and in a direction ofthe video signal wiring, and are arranged so that they mayperpendicularly mutually intersect.

[Method 10]

In the method 1 and 3, there was adopted a structure that the slitformed in the transparent pixel electrode in an active matrix substrateside and extending long and slender is arranged in a direction making±45 degrees to a direction of a scan signal wiring; and the slit forminga group with the liquid crystal alignment direction control electrodeare arranged in a parallel direction and in a perpendicular direction toa direction of the scan signal wirings; and the liquid crystal alignmentdirection control electrode encloses a periphery of the transparentpixel electrode while overlapping with the transparent pixel electrodevia the insulated film; and polarization axes of two polarizing platesplaced in exterior of a liquid crystal cell are arranged in thedirection of the scan signal wiring and in a direction of the videosignal wiring, and are arranged so that they may perpendicularlymutually intersect.

[Method 11]

In the method 1 and 3, there was adopted a structure that the slitformed in a transparent pixel electrode in an active matrix substrateside and extending long and slender is arranged in a parallel directionand in a perpendicular direction to the direction of the scan signalwiring; and the slit forming a group with the liquid crystal alignmentdirection control electrode is arranged in parallel to a direction ofthe scan signal wiring; and the liquid crystal alignment directioncontrol electrode encloses a periphery of the transparent pixelelectrode while overlapping with the transparent pixel electrode via theinsulated film; and polarization axes of two polarizing plates placed inexterior of a liquid crystal cell are arranged a direction of the scansignal wiring and in a direction of the video signal wiring, and arearranged so that they may perpendicularly mutually intersect.

[Method 12]

In the method 1 and 3, the slit formed in a transparent pixel electrodein an active matrix substrate side and extending long and slender isarranged in a parallel direction and in a perpendicular direction to adirection of the scan signal wiring; and the slit forming a group withthe liquid crystal alignment direction control electrode have astructure arranged in directions making ±45 degrees to a direction ofthe scan signal wiring; and polarization axes of two polarizing platesplaced in exterior of a liquid crystal cell are arranged in a directionof the scan signal wiring and in a direction of the video signal wiring,and are arranged so that they may perpendicularly mutually intersect.

[Method 13]

In the method 5 and 7, there was adopted a structure that the slitforming a group with the liquid crystal alignment direction controlelectrode are arranged in a parallel direction and in a perpendiculardirection to a direction of the scan signal wiring so as to enclose twoor more of circular or polygonal holes currently formed in thetransparent pixel electrode in an active matrix substrate side; and theliquid crystal alignment direction control electrode encloses aperiphery of the transparent pixel electrode while overlapping with thetransparent pixel electrode via the insulated film; and polarizationaxes of two polarizing plates placed in exterior of a liquid crystalcell are arranged in a direction of the scan signal wiring and in adirection of the video signal wiring, and are arranged so that they mayperpendicularly mutually intersect.

[Method 14]

In the method 1, 3, 5, and 7, the liquid crystal alignment directioncontrol electrode formed in a lower layer of the slit of the transparentpixel electrode via the insulated film is simultaneously formed in thesame layer at the time of formation of the scan signal wiring.

[Method 15]

In the methods 1, 3, 5, and 7, an additional capacitance was formed withthe liquid crystal alignment direction control electrode formed in alower layer of the slit of the transparent pixel electrode via theinsulated film, and the transparent pixel electrode.

[Method 16]

In the method 1 and 5, all of the scan signal wirings and the liquidcrystal alignment direction control electrodes are completely separated,and are connected to output terminals of different drive ICs,respectively; and contact buttons of the two rows of liquid crystalalignment direction control electrodes for controlling one row of pixelsare arranged so that they may be sandwiched between contact buttons ofdifferent scan signal wirings.

[Method 17]

In the method 3 and 7, all of the scan signal wirings and the liquidcrystal alignment direction control electrodes are completely separatedand independent, and are connected to output terminals of differentdrive ICs, respectively; and contact buttons of the one row of liquidcrystal alignment direction control electrodes for controlling one rowof pixels are arranged so that they may be sandwiched between contactbuttons of different scan signal wirings.

[Method 18]

In the method 1, 3, 5, and 7, contact buttons of the scan signal wiringare arranged in either of right side or left side of a display screenpart, and contact buttons of the liquid crystal alignment directioncontrol electrode are arranged on another side different from a side ofthe contact buttons of the scan signal wiring, each contact button ismutually completely separated and independent, and is connected tooutput terminals of different drive ICs, respectively.

[Method 19]

In the method 1 and 5, the scan signal wirings and the liquid crystalalignment direction control electrodes are completely separated andindependent, each contact button is arranged on both of right and leftsides of a display screen part, and contact buttons of the two rows ofthe liquid crystal alignment direction control electrodes forcontrolling one row of pixels are arranged so that they may besandwiched between contact buttons of different scan signal wirings.

[Method 20]

In the method 3 and 7, all of scan signal wirings and liquid crystalalignment direction control electrodes are completely separated andindependent, each contact button is arranged on both of right and leftsides of a display screen part, and contact buttons of the one row ofliquid crystal alignment direction control electrodes for controllingone row of pixels are arranged so that they may be sandwiched betweencontact buttons of different scan signal wirings.

[Method 21]

In the methods 2, 4, 6, and 8, at the time of moving image displaying, abias voltage impressed between the liquid crystal alignment directioncontrol electrode currently formed in a lower layer of the slit of thetransparent pixel electrode and the transparent pixel electrode is sethigher than a voltage at the time of still picture displaying, andthereby, a tilting speed of anisotropic liquid crystal molecules havinga negative dielectric constant are set higher.

[Method 22]

In order to impress a voltage to anisotropic liquid crystal moleculeshaving a negative dielectric constant that are vertically aligned to anactive matrix substrate and a color filter substrate and to make theliquid crystal molecules tilt in different two directions or differentfour directions, two kinds of following electrode structure andstructure arrangement were formed in one pixel of the active matrixsubstrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns (no transparent electrode in a slit part) having a shape of along and slender slit are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, and aliquid crystal alignment direction control electrode having almost thesame shape as a shape of the slit, and a larger dimension than adimension of the slit are formed in a lower layer of the slit via aninsulated film.iii) In a pixel of n row m column, a thin film transistor element isformed in a position where a scan signal wiring of (n−1) row and a videosignal wiring of (m+1) column intersect with each other, and a videosignal wiring of (m+1) column and a liquid crystal alignment directioncontrol electrode used for a pixel of n row m column are connected viathe thin film transistor element; and a thin film transistor element isformed in a position where a scan signal wiring of n row and a videosignal wiring of m column intersect, and a video signal wiring of mcolumn and a transparent pixel electrode used for a pixel of n row mcolumn are connected via the thin film transistor element.[Method 23]

In order to impress a voltage to anisotropic liquid crystal moleculeshaving a negative dielectric constant that are vertically aligned to anactive matrix substrate and a color filter substrate and to make theliquid crystal molecules tilt in different two directions or differentfour directions, two kinds of following electrode structure andstructure arrangement were formed in one pixel of the active matrixsubstrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns (no transparent electrode in a slit part) having a shape of along and slender slit are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, and aliquid crystal alignment direction control electrode having almost thesame shape as a shape of the slit, and a larger dimension than adimension of the slit is formed in a lower layer of the slit via aninsulated film.iii) In a pixel of n row m column, a thin film transistor element isformed on a scan signal wiring of (n−1) row, a common electrode of nrow, and a liquid crystal alignment direction control electrode used fora pixel of n row m column are connected via the thin film transistorelement, and a thin film transistor element is formed in a positionwhere a scan signal wiring of n row and a video signal wiring of mcolumn intersect with each other, and the video signal wiring of mcolumn, and a transparent pixel electrode used for a pixel of n row mcolumn are connected via the thin film transistor element.[Method 24]

In order to impress a voltage to liquid crystal molecules that arevertically aligned to an active matrix substrate and a color filtersubstrate and to make the liquid crystal molecules tilt in manydirections, two kinds of following electrode structure and structurearrangement were formed in one pixel of the active matrix substrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,circular or polygonal holes (no transparent electrodes in a portion of ahole) are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, a liquidcrystal alignment direction control electrode having almost the sameshape as a shape of the slit, and a larger dimension than a dimension ofthe slit are formed in a lower layer of the slit via the insulated film.iii) In a pixel of n row m column, a thin film transistor element isformed in a position where a scan signal wiring of (n−1) row and a videosignal wiring of (m+1) column intersect with each, and a video signalwiring of (m+1) column and a liquid crystal alignment direction controlelectrode used for a pixel of n row m column are connected via the thinfilm transistor element; and a thin film transistor element is formed ina position where a scan signal wiring of n row and a video signal wiringof m column intersect with each other, and the video signal wiring of mcolumn and a transparent pixel electrode used for pixel of n row mcolumn are connected via the thin film transistor element.[Method 25]

In order to impress a voltage to liquid crystal molecules that arevertically aligned between an active matrix substrate and a color filtersubstrate and to make the liquid crystal molecules tilt in manydirections, two kinds of following electrode structures and structurearrangements were formed in one pixel of the active matrix substrate.

i) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate sidemany circular or polygonal holes (no transparent electrodes in a portionof a hole) are formed.ii) A transparent flat common electrode is used in a color filtersubstrate side, and for transparent pixel electrodes countering thetransparent flat common electrode in the active matrix substrate side,patterns having a shape of a long and slender slit are formed, and aliquid crystal alignment direction control electrode having almost thesame shape as a shape of the slit, and a larger dimension than adimension of the slit are formed in a lower layer of the slit via aninsulated film.iii) In a pixel of n row m column, a thin film transistor element isformed on a scan signal wiring of (n−1) row, a common electrode of n rowand a liquid crystal alignment direction control electrode used for apixel of n row m column are connected via the thin film transistorelement, and a thin film transistor element is formed in a positionwhere a scan signal wiring of n row and a video signal wiring of mcolumn intersect with each other, and the video signal wiring of mcolumn and a transparent pixel electrode used for a pixel of n row mcolumn are connected via the thin film transistor element.[Method 26]

In the methods 22, 23, 24, and 25, a time width of a scan signalwaveform in the scan signal wiring is no less than two times of ahorizontal period, a scan signal waveform in a scan signal wiring of(n−1)th row and a scan signal waveform in a scan signal wiring of (n)throw overlap one another by no less than one time of a horizontal period;and polarities of a video signal voltage of a video signal wiring of mcolumn, and a video signal voltage of a video signal wiring of (m+1)column are different from each other, and the polarities being mutuallyexchanged every horizontal period, and the polarities being mutuallyexchanged every vertical period.

[Method 27]

In the methods 22 and 24, a channel length (L₂) of a thin filmtransistor element that is formed in a position where a scan signalwiring of (n−1) row and a video signal wiring of column (m+1) intersect,and is connected with the liquid crystal alignment direction controlelectrode was set larger than a channel length (L₁) of a thin filmtransistor element that is formed in a position where a scan signalwiring of n row and a video signal wiring of m column intersect, and isconnected with the transparent pixel electrode (L₁<L₂).

[Method 28]

In the methods 23 and 25, a channel length (L₂) of a thin filmtransistor element that is formed on a scan signal wiring of (n−1) row,and is connected with the liquid crystal alignment direction controlelectrode was set larger than a channel length (L₁) of a thin filmtransistor element that is formed in a position where a scan signalwiring of n row and a video signal wiring of m column intersect, and isconnected with the transparent pixel electrode (L₁<L₂).

[Method 29]

In the methods 22, 23, 24, and 25, a double transistor element structureor an offset channel element structure was used for a thin filmtransistor element connected with the liquid crystal alignment directioncontrol electrode.

[Method 30]

In the methods 22 and 23, a slit formed in the transparent pixelelectrode in the active matrix substrate side and extending long andslender, and a slit forming a group with the liquid crystal alignmentdirection control electrode are arranged alternately, maintaining arelationship almost parallel to each other in an angle direction ofabout ±45 degrees to an extending direction of the scan signal wiring;polarization axes of two polarizing plates placed in exterior of aliquid crystal cell are arranged in a direction of the scan signalwiring and in a direction of the video signal wiring, and are arrangedso that they may perpendicularly mutually intersect.

[Method 31]

In the methods 22 and 23, a slit formed in a transparent pixel electrodein the active matrix substrate side and extending long and slender arearranged in a parallel direction and in a perpendicular direction to anextending direction of the scan signal wiring; and a slit forming agroup with the liquid crystal alignment direction control electrode isarranged in a angle direction of about ±45 degrees to a direction of thescan signal wirings; and polarization axes of two polarizing platesplaced in exterior of a liquid crystal cell are arranged in a directionof the scan signal wiring and in a direction of the video signal wiring,and are arranged so that they may perpendicularly mutually intersect.

[Method 32]

In methods 22 and 23, there was adopted a structure that a slit formedin the transparent pixel electrode in the active matrix substrate sideand extending long and slender is arranged in a angle direction of about±45 degrees to an extending direction of the scan signal wiring; and aslit forming a group with the liquid crystal alignment direction controlelectrode is arranged in a parallel direction and in a perpendiculardirection to an extending direction of the scan signal wiring; and theliquid crystal alignment direction control electrode encloses aperiphery of the transparent pixel electrode while overlapping with thetransparent pixel electrode via the insulated film; and polarizationaxes of two polarizing plates placed in exterior of a liquid crystalcell are arranged in a direction of the scan signal wiring and in adirection of the video signal wiring, and are arranged so that they mayperpendicularly mutually intersect.

[Method 33]

In methods 24 and 25, there was adopted a structure that a slit forminga group with the liquid crystal alignment direction control electrode isarranged in a direction perpendicular to a direction parallel to anextending direction of the scan signal wiring so that two or morecircular or polygonal holes currently formed in the transparent pixelelectrode in the active matrix substrate side may be surrounded; and theliquid crystal alignment direction control electrode encloses aperiphery of the transparent pixel electrode while overlapping with thetransparent pixel electrode via the insulated film; and polarizationaxes of two polarizing plates placed in exterior of a liquid crystalcell are arranged in a direction of the scan signal wiring and in adirection of the video signal wiring, and are arranged so that they mayperpendicularly mutually intersect.

[Method 34]

In the methods 22, 23, 24, and 25, the liquid crystal alignmentdirection control electrode formed in a lower layer of a slit of thetransparent pixel electrode via the insulated film is simultaneouslyformed in the same layer at the time of formation of the scan signalwiring.

[Method 35]

In the methods 22 and 23, the liquid crystal alignment direction controlelectrode formed in a lower layer of a slit of the transparent pixelelectrode via the insulated film is simultaneously formed in the samelayer at the time of formation of the video signal wiring.

[Method 36]

In the method 22, two thin film transistor elements are required in onepixel in order to drive the one pixel and only one contact hole existsfor electrically connecting a drain electrode of a thin film transistorelement formed in a position where a scan signal wiring of n row and avideo signal wiring of m column intersect with each other, and thetransparent pixel electrode.

[Method 37]

In the methods 22 and 24, two thin film transistor elements are requiredin one pixel in order to drive the one pixel and two contact holes existfor electrically connecting a drain electrode of a thin film transistorelement formed in a position where a scan signal wiring of (n−1) row anda video signal wiring of (m+1) column intersect with each other, and theliquid crystal alignment direction control electrode; and only onecontact hole exists for electrically connecting a drain electrode of athin film transistor element formed in a position where a scan signalwiring of n row and a video signal wiring of m column intersect witheach other, and the transparent pixel electrode.

[Method 38]

In the methods 22, 23, 24, and 25, two thin film transistor elements arerequired in one pixel in order to drive the one pixel and one thin filmtransistor element is connected to the transparent pixel electrode,another remaining thin film transistor element is connected to theliquid crystal alignment direction control electrode, and thetransparent pixel electrode and the liquid crystal alignment directioncontrol electrode were overlapped via the insulated film to form acapacitance.

[Method 39]

In the methods 22, 23, 24, and 25, an intermediate electrode of a thinfilm transistor element connected with the liquid crystal alignmentdirection control electrode and having a double transistor structure andthe transparent pixel electrode overlap via the insulated film to form acapacitance.

[Method 40]

In the methods 22 and 24, a transparent pixel electrode of n row and mcolumn and a scan signal wiring of (n−1)th row may overlap one anothervia an insulated film to form a storage capacitor.

[Method 41]

In the methods 23 and 25, a transparent pixel electrode of n row and mcolumn and a common electrode of n row may overlap one another via theinsulated film to form a storage capacitor.

Use of the methods 1, 2, 3, 4, 5, 6, 7, and 8, enables anisotropicliquid crystal molecules having a negative dielectric constant in astate of being vertically aligned to tilt in a target direction, asshown in FIG. 2, FIG. 3, FIG. 5, and FIG. 6.

This makes unnecessary formation of a bump 5 that had to be formed on acolor filter side substrate of a vertically aligned mode liquid crystaldisplay, for motion directional control of liquid crystal molecules, asis shown in conventional method FIG. 1. Moreover, this enablesmanufacture of a multi-domain vertically aligned mode liquid crystaldisplay using a cheap color filter, as shown in FIG. 4.

Furthermore, only alignment layers 6 and 7 and anisotropic liquidcrystal molecules having a negative dielectric constant 14 exist betweena flat common electrode 4 in a color filter side, and a transparentpixel electrode 8 of an active matrix substrate as shown in FIG. 4,which completely solves problems, such as diffusion of contaminants fromthe bump 5, and remarkably improves reliability.

Additionally, even in case of failure in application of an alignmentlayer, omission of bump 5 enables simple and short time regenerationwith oxygen plasma by a dry-asher. That is, in surface treatment processbefore alignment layer application, a plasma treatment with oxygen andargon using a dry-asher becomes usable, which remarkably decreaserepelling and generation of pinhole in alignment layer applicationprocess.

Use of the methods 9, 10, 11, 12, and 13 may sharply improve effectiveuse efficiency of polarizing plates, and thereby may reduce a cost ofpolarizing plates used for very large-sized liquid crystal displays. Inaddition, effective use efficiency of a polarizer having reflexibilitycomprising multilayer laminated body of two kinds of materials used fora backlight may also be sharply improved, which may also reduce cost ofa backlight for very large-sized liquid crystals display. Moreover,possibility of control for a motion direction of liquid crystalmolecules in four directions may provide wide viewing angles.

Use of the methods 14 and 15 enables manufacture of an active matrixsubstrate of the present invention using completely same processes,without changing manufacturing processes of conventional active matrixsubstrate.

In addition, since a liquid crystal alignment direction controlelectrode is arranged close to both sides of a video signal wiring and,as shown in FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG. 14, FIG. 16, FIG. 17,FIG. 18, and FIG. 25, a potential variation of a video signal wiring iseasily shielded, which may completely control a cross talk generation ina perpendicular direction.

Use of the methods 16, 17, 18, 19, and 20 enables separate drive forevery row of liquid crystal alignment direction control electrodescurrently formed in a lower layer of slits of transparent pixelelectrodes of each row, enabling uniform display by same conditions inall portions of upper part, central part, and lower part of a displayscreen.

Use of the methods 2, 4, 6, 8, and 21 enables anisotropic liquid crystalmolecules having a negative dielectric constant in a state of beingvertically aligned to tilt in a target direction, preventing generationof disclination to enable uniform half tone display. Additionally, useof the method of the present invention may sharply improve a lateresponse speed, in a change to a half tone display from a black display,and to a half tone display from a white display, that has been a problemin a conventional vertically aligned mode liquid crystal display mode.In case of responding animated pictures, increase of a bias voltageimpressed between a certain transparent pixel electrode and a liquidcrystal alignment direction control electrode formed in a lower layer ofslits of the transparent pixel electrode may further improve a speed ofresponse. In the present invention, since a display approaches closer toblack display and the above-mentioned bias voltage may become larger, aspeed of response is improvable in all regions.

Use of the methods 22, 23, 24, 25, and 26 makes unnecessary formation ofa bump 5 in a color filter (CF) substrate 3 for motion directionalcontrol of liquid crystal molecules as is shown in FIG. 1 ofconventional methods, which may enable a simple color filter structureas is shown in FIG. 34, FIG. 40, FIG. 45, and FIG. 46 to realize lowprice. Furthermore, a problem of diffusion into liquid crystals ofcontaminant from bumps, which conventionally has been a problem, maycompletely be solved, and also a problem of unevenness in a half tonearea induced from heterogeneity of shape of the bumps may completely bewiped away, leading to simultaneous realization of remarkableimprovement in yield, and improvement in reliability.

Moreover, since a method of the present invention does not requirebumps, in failure in application of an alignment layer, regeneration canbe easily performed in a short time using oxygen plasma by a dry-asher.In surface treatment process before alignment layer application, aplasma treatment with oxygen and argon using a dry-asher becomes usable,which remarkably decrease repelling and generation of pinhole inalignment layer application process.

Use of the methods 22, 23, 24, 25, 26, 27, 28, 29, and 39 makesunnecessary special drive ICs for driving liquid crystal alignmentdirection control electrodes, and contact button parts, which mayrealize low price products. Furthermore, use of a double transistorstructure, or an offset transistor structure may reduce leakage current.Since electric field is dispersed and concentration is prevented, evenif a large voltage is impressed between a source and a drain electrodeof a transistor, shift of a threshold voltage (Vth) of thin filmtransistors is reduced, leading to realization of a reliable liquidcrystal panel. Increase in a channel length (L₂) of thin film transistorelements connected to liquid crystal alignment direction controlelectrodes may reduce a leakage current.

Use of the methods 22, 23, 24, 25, 26, 30, 31, 32, and 33 may sharplyimprove effective use efficiency of a polarizing plate compared withconventional liquid crystal panels in TN (Twisted Nematic) mode, whichmay reduce a cost of a polarizing plate used in very large-sized liquidcrystal displays. In addition, effective use efficiency of a polarizerhaving reflexibility comprising multilayer laminated body of two kindsof materials (brand name: DBEF by 3M Inc.) used for a backlight may alsobe sharply improved, which may also reduce a cost of a backlight forvery large-sized liquid crystal displays.

Since use of the methods 22, 23, 24, 25, 34, and 35 enables manufactureof active matrix liquid crystal panels of the present invention usingsame processes, without changing most of conventional manufacturingprocesses of an active matrix substrate and manufacturing processes of acolor filter in TN mode, leading to demonstration of predominancy inrespect of yield and low cost.

Use of the methods 22, 23, 24, 25, 26, 36, 37, and 38 may realizevertically aligned mode liquid crystal display having a simpleststructure. This method does not have excessive and unnecessary thin filmtransistor elements in one pixel, but an aperture ratio may be set largein the highest, being able to realize a bright display.

Since use of the methods 22, 23, 24, 25, 26, 27, 28, 29, and 39 enablesimpression of a large voltage between a transparent pixel electrode anda liquid crystal alignment direction control electrode, deformation ofan electric field for driving vertically aligned liquid crystalmolecules may be set significantly large. This may improve a rate ofreaction of the liquid crystal molecules, and even in moving imagedisplaying, a flow of image and a residual image phenomenon are scarcelygenerated.

When a scanning line of n row is set as OFF, use of the methods 22, 23,24, 25, 40, and 41 may decrease a potential variation of a transparentpixel electrode, and reduce flicker.

Use of the methods 22, 23, 24, 25, and 26 may provide vertically alignedliquid crystal molecules with alignment almost perpendicular in allareas at the time of black display, which reduces light leakage morethan in conventional methods using bumps, and may realize completelyuniform black display also in a dark room.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section structural figure of a conventionalmulti-domain vertically aligned mode liquid crystal panel;

FIG. 2 shows a motion direction of molecules of anisotropic liquidcrystal having a negative dielectric constant vertically aligned by anelectric field formed with a flat electrode and a slit electrode;

FIG. 3 shows a motion direction of molecules of anisotropic liquidcrystal having a negative dielectric constant vertically aligned by anelectric field formed with a flat electrode, a slit electrode, andliquid crystal alignment direction control electrode;

FIG. 4 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 5 shows a drive principle cross section structural figure of amulti-domain vertically aligned mode liquid crystal panel of the presentinvention (when a pixel electrode has negative data);

FIG. 6 shows a drive principle cross section structural figure of amulti-domain vertically aligned mode liquid crystal panel of the presentinvention (when a pixel electrode has positive data);

FIG. 7 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 8 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 9 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 10 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 11 shows a waveform chart of a voltage impressed to a thin filmtransistor element of an odd number column of (n)th row and (n+1)th rowof a multi-domain vertically aligned mode liquid crystal panel of thepresent invention;

FIG. 12 shows a waveform chart of a voltage impressed to a thin filmtransistor element of an even number column of (n)th row and (n+1)th rowof a multi-domain vertically aligned mode liquid crystal panel of thepresent invention;

FIG. 13 shows a plan view of contact button parts of scanning lines andliquid crystal alignment direction control electrodes of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 14 shows a plane structural figure of a vertically aligned modeliquid crystal panel of the present invention;

FIG. 15 shows a plan view of a vertically aligned mode active matrixsubstrate of the present invention;

FIG. 16 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 17 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 18 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 19 shows a plan view of contact button parts of scanning lines andliquid crystal alignment direction control electrodes of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 20 shows a plan view of a vertically aligned mode active matrixsubstrate of the present invention;

FIG. 21 shows a plan view of a vertically aligned mode active matrixsubstrate of the present invention;

FIG. 22 shows a waveform of a voltage impressed to a thin filmtransistor element corresponding to a pixel of an odd number column of(n)th row and of (n+1)th row of a multi-domain vertically aligned modeliquid crystal panel of the present invention;

FIG. 23 shows a waveform of a voltage impressed to a thin filmtransistor element corresponding to a pixel of an even number column of(n)th row and of (n+1)th row of a multi-domain vertically aligned modeliquid crystal panel of the present invention;

FIG. 24 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 25 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 26 shows a plan view of a vertically aligned mode active matrixsubstrate of the present invention;

FIG. 27 shows a plan view of a vertically aligned mode active matrixsubstrate of the present invention;

FIG. 28 shows a plan view and a cross section structural figure of slitsformed in a liquid crystal alignment direction control electrode and atransparent pixel electrode of the present invention;

FIG. 29 shows a plan view and a cross section structural figure of slitsformed in a liquid crystal alignment direction control electrode and atransparent pixel electrode of the present invention;

FIG. 30 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 31 shows a drive principle cross section structural figure of amulti-domain vertically aligned mode liquid crystal panel of the presentinvention (when a pixel electrode has negative data);

FIG. 32 shows a drive principle cross section structural figure of amulti-domain vertically aligned mode liquid crystal panel of the presentinvention (when pixel electrode has positive data);

FIG. 33 shows a waveform chart of a voltage impressed to a thin filmtransistor element of an odd number column (n)th row, and (n+1)th row ofa multi-domain vertically aligned mode liquid crystal panel of thepresent invention;

FIG. 34 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 35 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 36 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 37 shows a drive voltage waveform of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 38 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 39 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 40 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 41 shows a plane structural figure of slits formed in a liquidcrystal alignment direction control electrode and a transparent pixelelectrode of the present invention;

FIG. 42 shows a plane structural figure of slits formed in a liquidcrystal alignment direction control electrode and a transparent pixelelectrode of the present invention;

FIG. 43 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 44 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 45 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 46 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 47 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 48 shows a table showing potentials of A and B in the circuit modelfigure of FIG. 47;

FIG. 49 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 50 shows a table showing potentials of A and B in the circuit modelfigure of FIG. 47;

FIG. 51 shows a description of a flow of five-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 52 shows a description of a flow of four-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 53 shows a description of a flow of five-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 54 shows a description of a flow of four-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 55 shows a description of a flow of five-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 56 shows a description of a flow of four-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 57 shows a description of a flow of five-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 58 shows a description of a flow of four-photo-mask-process for amulti-domain vertically aligned mode liquid crystal panel manufacturingof the present invention;

FIG. 59 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 60 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 61 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 62 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 63 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 64 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 65 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 66 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 67 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 68 shows a cross section structural figure of a multi-domainvertically aligned mode liquid crystal panel of the present invention;

FIG. 69 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 70 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 71 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 72 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 73 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 74 shows a circuit model figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 75 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 76 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 77 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 78 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 79 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 80 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 81 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 82 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 83 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 84 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 85 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 86 shows a partial plan view of a multi-domain vertically alignedmode liquid crystal panel of the present invention;

FIG. 87 shows a plan view of an offset thin film transistor element formulti-domain vertically aligned mode liquid crystal panels of thepresent invention;

FIG. 88 shows a sectional view of an offset thin film transistor elementfor multi-domain vertically aligned mode liquid crystal panels of thepresent invention;

FIG. 89 shows a sectional view of an offset thin film transistor elementfor multi-domain vertically aligned mode liquid crystal panels of thepresent invention;

FIG. 90 shows a sectional view of an offset thin film transistor elementfor multi-domain vertically aligned mode liquid crystal panels of thepresent invention;

FIG. 91 shows a sectional view of a double gate thin film transistorelement for multi-domain vertically aligned mode liquid crystal panelsof the present invention;

FIG. 92 shows a sectional view of a double gate thin film transistorelement for multi-domain vertically aligned mode liquid crystal panelsof the present invention;

FIG. 93 shows a plane structural figure of slits formed in a liquidcrystal alignment direction control electrode and a transparent pixelelectrode of the present invention;

FIG. 94 shows a plane structural figure of slits formed in a liquidcrystal alignment direction control electrode and a transparent pixelelectrode of the present invention;

FIG. 95 shows a plane structural figure of slits formed in a liquidcrystal alignment direction control electrode and a transparent pixelelectrode of the present invention;

FIG. 96 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 97 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 98 shows a plane structural figure of a multi-domain verticallyaligned mode liquid crystal panel of the present invention;

FIG. 99 shows a motion direction of molecules of anisotropic liquidcrystal having a negative dielectric constant vertically aligned by anelectric field formed with a flat electrode and a slit electrode;

FIG. 100 shows a motion direction of molecules of anisotropic liquidcrystal having a negative dielectric constant vertically aligned by anelectric field formed with a flat electrode, a slit electrode, and aliquid crystal alignment direction control electrode; and

FIG. 101 shows a motion direction of molecules of anisotropic liquidcrystal having a negative dielectric constant vertically aligned by anelectric field formed with a flat electrode, a slit electrode, and aliquid crystal alignment direction control electrode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, with reference to accompanying drawings, description aboutdesirable Example of the present invention will be provided.

Example 1

FIGS. 4, 5, and 6 show sectional views of Example 1 of the presentinvention. A color filter substrate 1 has a flat transparent commonelectrode 4, and an active matrix substrate 13 is arranged facing thesubstrate 1 and in parallel.

In the active matrix substrate 13, firstly, a scan signal wiring 17 anda liquid crystal alignment direction control electrode 15 aresimultaneously formed in the same layer, and subsequently, a gateinsulator film 12, an amorphous silicone layer, and an n⁺ amorphoussilicone layer for ohmic contacts are deposited.

After formation of a thin film transistor element part, a video signalwiring 11 and a drain electrode are formed.

Next, a contact hole 18 is formed in a portion of a drain electrodeafter deposition of a passivation film 10, and then a transparentelectric conductive film is deposited. In the transparent electricconductive film, as shown in FIG. 7, some slits are formed and eachpixel is completely separated for every pixel to provide a transparentpixel electrode 8.

An electrode structure of the present invention has following specialfeatures: there exist one another in one pixel a portion in which a longand slender slit 9, or a circular or polygonal hole is formed facing aflat transparent common electrode 4 on a color filter side, as shown inFIG. 2; and a portion in which a long and slender slit and a liquidcrystal alignment direction control electrode 15 having almost the sameshape as the slit, and having a larger dimension than a dimension of theslit are formed facing the flat transparent common electrode 4 on acolor filter side, as shown in FIG. 3.

As shown in FIG. 5 and FIG. 6, these two kinds of electrode structurescontrol to tilt correctly anisotropic liquid crystal molecules having anegative dielectric constant 14 in two directions, four directions, ormany directions, that is, in target directions within one pixel.Distribution of equipotential lines is shown in FIG. 2 and FIG. 3.

As shown in FIG. 4, FIG. 5, and FIG. 6, in Example 1, liquid crystalalignment direction control electrodes 15 are arranged close to both ofright and left sides of a video signal wiring 11. Since the liquidcrystal alignment direction control electrode 15 shields a signalvoltage variation of the video signal wiring 11, effect of the videosignal wiring 11 is not transmitted to the transparent pixel electrode8. As compared with conventional vertically aligned mode liquid crystaldisplays shown in FIG. 1, a vertically aligned mode liquid crystaldisplay of the present invention of FIG. 4 generates very littleperpendicular stroke. Since a width of BM (shading film (Black Matrix))2 of a color filter may also be set more narrowly than in conventionalproducts, a vertically aligned mode liquid crystal display with a largeaperture ratio may be realizable.

Example 2

FIG. 30, FIG. 31, and FIG. 32 show sectional views of Example 2 of thepresent invention. In fundamental aspect, almost the same structure asin Example 1 is used for Example 2. An electrode structure of theExample has special features that two kinds of electrode structures asshown in FIG. 2 and FIG. 3 exist together in one pixel.

As shown in FIG. 30, FIG. 31, and FIG. 32, since a video signal wiring11 is only sandwiched by transparent pixel electrodes 8 from both ofright and left sides, capacitance of a video signal wiring 11 can bedesigned minimal, and accordingly, even if a resistance of the videosignal wiring 11 is high, a problem of signal delay is hard to begenerated.

FIG. 24 shows a plan view of Example 2. Only one row of liquid crystalalignment direction control electrode 15 exists in one pixel. Adjacenttransparent pixel electrodes 8 are connected to a thin film transistorelement 16 controlled by a different scan signal wiring 17,respectively.

As a plan view of FIG. 24 shows, since an area in which the liquidcrystal alignment direction control electrode 15 exists close to a scansignal wiring 17 is small, even if the scan signal wiring 17 and theliquid crystal alignment direction control electrode 15 aresimultaneously formed in the same layer, a probability that a defect inwhich electric short-circuit is provided by a connection of each otherwill occur is extremely small.

Slits 9 are formed in a direction parallel direction and a perpendiculardirection to the scan signal wiring 17, and slits forming a group with aliquid crystal alignment direction control electrode 15 are extended inangle directions of ±45 degrees to the scan signal wiring direction.Slits forming a group with a liquid crystal alignment direction controlelectrode may have a form like connected diamond-shapes, and may have aform like squares located in a line as shown in FIG. 28 and FIG. 29.

Example 3

FIG. 7 shows a plan view of Example 3 of the present invention. TheExample has a structure where two kinds of structures, a structure shownin a cross section structural figure of Example 1 and a structure shownin a cross section structural figure of Example 2, are mixed inside onepixel. In one pixel, two rows of liquid crystal alignment directioncontrol electrodes of an upper liquid crystal alignment directioncontrol electrode 19 and a lower liquid crystal alignment directioncontrol electrode 20 are arranged, each potential is set as positiveelectrode potential and negative electrode potential on the basis of apotential of a countering flat common electrode 4 of a color filter sidesubstrate. Adjacent transparent pixel electrodes 8 are controlled by adifferent liquid crystal alignment direction control electrode,respectively.

FIG. 11 and FIG. 12 show a transparent common electrode potential 21, avideo signal wiring waveform 22 of odd number column, a scanning linesignal waveform 23 of n row, a scanning line signal waveform 24 of (n+1)row, an upper liquid crystal alignment direction control electrodesignal waveform 25 of n row, a lower liquid crystal alignment directioncontrol electrode signal waveform 26 of n row, an upper liquid crystalalignment direction control electrode signal wave form 27 of (n+1) row,a lower liquid crystal alignment direction control electrode signal waveform 28 of (n+1) row, and a video signal wiring waveform 29 of evennumber column.

As shown in FIG. 11 and FIG. 12, when a signal having a positivepolarity is written in a transparent pixel electrode 8, a potential of aliquid crystal alignment direction control electrode currently formedvia an insulator film 12 in a lower layer of a slit 9 of the transparentpixel electrode 8 has a positive polar potential higher than a potentialof the transparent pixel electrode 8, and when a signal having anegative polarity is written in the transparent pixel electrode 8, apotential of a liquid crystal alignment direction control electrodecurrently formed via an insulator film 12 in a lower layer of a slit 9of the transparent pixel electrode 8 has a negative polar potentiallower than a potential of the transparent pixel electrode 8.

Transparent pixel electrode 8, and liquid crystal alignment directioncontrol electrodes 19 and 20 of two rows arranged in one pixel haveexchanged polarity, respectively, every perpendicular period.

As shown in FIG. 7, slits 9 currently formed in a transparent pixelelectrode 8 and liquid crystal alignment direction control electrodes 19and 20 arranged in a lower layer of the slit are arranged so as to makeangles of ±45 degrees to a direction of a scan signal wiring 17.

In an upper half and a lower half in one pixel, the slit 9 and theliquid crystal alignment direction control electrodes 19 and 20 of alower layer of the slit, respectively, are arranged alternately andalmost in parallel each other. Special feature is that a liquid crystalalignment direction control electrode is arranged in a central part ofthe pixel so as to divide the upper half and the lower half. Polarizingplates are arranged so that polarization axes may become parallel andperpendicular to the scan signal wiring 17 and may have a relationshipof intersecting mutually perpendicular, in an exterior of the liquidcrystal cell.

Example 4

FIG. 8, FIG. 9, and FIG. 10 show a plan view of Example 4 of the presentinvention. This Example adopts a cross section structural figure ofExample 1, and liquid crystal alignment direction control electrodes 19and 20 enclose periphery of a transparent pixel electrode 8, which makesit difficult that the transparent pixel electrode 8 is influenced by apotential variation of a video signal wiring 11, and thus hardlygenerates a perpendicular cross talk. Moreover, since liquid crystalalignment direction control electrodes 19 and 20 and the transparentpixel electrode 8 are overlapped, a width of a shading film 2 of a colorfilter (BM) may be narrowed, and an aperture ratio may be increased.

In addition, liquid crystal alignment direction control electrodes 19and 20 of two rows exist in one pixel, and thereby almost the samesystem as the drive system in Example 3 may be used.

In FIG. 8, slits 9 formed in the transparent pixel electrode 8 arearranged in directions of ±45 degrees to a direction of the scan signalwirings. In FIG. 9, slits 9 formed in the transparent pixel electrode 8are arranged in two directions perpendicular and horizontal to adirection of the scan signal wirings. In FIG. 10, fine notches of slitare formed in motion directions of liquid crystal molecules in thetransparent pixel electrode 8. Arrangement of polarizing plates may becompletely the same arrangement as an arrangement in Example 3.

Example 5

FIG. 14 shows a plan view of Example 5 of the present invention. ThisExample adopts a cross section structural figure of Example 1, andliquid crystal alignment direction control electrodes 19 and 20 encloseperiphery of a transparent pixel electrode 8, which makes it difficultthat the transparent pixel electrode 8 is influenced by a potentialvariation of a video signal wiring 11, and thus hardly generates aperpendicular cross talk. This Example differs from Example 4 in a pointthat many circular holes 37 are formed in the transparent pixelelectrode 8. As long as they are holes, polygonal forms may be of anykinds other than a circular form. Liquid crystal alignment directioncontrol electrodes 19 and 20 of two rows exist in one pixel, and thesame drive system as in Example 3 may be used. Arrangement of polarizingplates may be the same arrangement as an arrangement in Example 3.

Example 6

FIG. 16 shows a plan view of Example 6 of the present invention. ThisExample has a structure where two kinds, a cross section structuralfigure of Example 1 and a cross section structural figure of Example 2,are mixed inside one pixel. A liquid crystal alignment direction controlelectrode 15 of one row is arranged in one pixel, and adjacenttransparent pixel electrodes 8 are connected, respectively, with a thinfilm transistor element 16 currently controlled by a different scansignal wiring 17. Forms of a long and slender slit 9 currently formed inthe transparent pixel electrode 8 and of the liquid crystal alignmentdirection control electrode 15 currently formed in a lower layer of theslit via an insulator film 12 are almost the same as in Example 3, andare arranged to make angles of ±45 degrees to the direction of scansignal wiring 17.

In an upper half and a lower half in one pixel, the slit 9 and theliquid crystal alignment direction control electrode 15 formed in alower layer of the slit, respectively, are arranged alternately andalmost in parallel each other. A liquid crystal alignment directioncontrol electrode 15 is arranged that divides an upper half and a lowerhalf in a central part of a pixel. Polarizing plates are arranged sothat polarization axes may become parallel and perpendicular to the scansignal wiring 17 and may have a relationship of intersecting mutuallyperpendicular, in an exterior of the liquid crystal cell.

In all Examples of the present invention, a transparent pixel electrode8, and liquid crystal alignment direction control electrodes 15, 19, and20 overlap mutually via the insulator film 12, and form an additionalcapacity (storage capacitor). When a larger additional capacity isrequired, an overlapping area may be set larger. When a smalleradditional capacity is required, an overlapping area may be set smaller.In an usual range, an overlapping width of about 2 micron (2micrometers) provides a sufficient additional capacity.

FIG. 22 and FIG. 23 show a driving method of Example 6. A driving methodof the Example differs from a driving method of Example 3a little.

FIG. 22 and FIG. 23 show a transparent common electrode potential 21, avideo signal wiring waveform of odd number column 22, a scanning linesignal waveform of n row 23, a scanning line signal waveform of row(n+1) 24, a video signal wiring waveform of even number column 29, and ascanning line signal waveform of (n−1) row 43.

In Example 3, there is used a method that adjacent transparent pixelelectrodes 8 are controlled by the same scan signal wiring 17 in Example3, and video signals having different polarity, respectively, arewritten in from a video signal wiring 11. In Example 6, there is used amethod that adjacent transparent pixel electrodes 8 are controlled by adifferent scan signal wiring 17, and video signals having the samepolarity are written in after a shift of one horizontal scanning-periodfrom a video signal wiring 11. As FIG. 22 and FIG. 23 show, when apositive signal is written in a transparent pixel electrode, a potentialof a liquid crystal alignment direction control electrode has a positivepolar potential higher than the transparent pixel electrode, and when anegative signal is written in the transparent pixel electrode, apotential of the liquid crystal alignment direction control electrodehas a negative polar potential lower than the transparent pixelelectrode. The transparent pixel electrode and the liquid crystalalignment direction control electrode reverse each polarity for everyperpendicular period.

In all Examples of the present invention, it is possible to tiltmolecules of anisotropic liquid crystal having a negative dielectricconstant 14 in a target direction from a perpendicular direction bysetting a potential difference between a transparent pixel electrode 8and liquid crystal alignment direction control electrodes 15, 19, and20. In this case tilt angle may only be one-two degrees from aperpendicular direction (90 degrees). Usually, a bias potential of noless than 4-5 V is impressed. When a high-speed response is required, itis necessary to set a tilt angle as no less than 10 degrees, and a biaspotential of no less than 6-8 V is impressed in this case. When thepresent invention is used for a liquid crystal TV, it is effective toset a bias potential between a transparent pixel electrode 8 and liquidcrystal alignment direction control electrodes 15, 19, and 20 larger.When the present invention is made to serve a double purpose for aviewing display for computers, and for a moving image displayingapparatus for TV, it is effective to perform a circuit design so thatthis bias potential may be variable.

Example 7

FIG. 17 and FIG. 18 show plan view of Example 7 of the presentinvention. This Example adopts a cross section structural figure ofExample 1, a liquid crystal alignment direction control electrode 15encloses a periphery of a transparent pixel electrode 8, which makes itdifficult that the transparent pixel electrode 8 is influenced by apotential variation of a video signal wiring 11, and hardly generates aperpendicular cross talk. One row of liquid crystal alignment directioncontrol electrode 15 exists in one pixel, and adjacent transparent pixelelectrodes 8 are connected to a thin film transistor element 16controlled by a different scan signal wiring 17, respectively. A drivingmethod of this Example is same as in Example 6. Arrangement ofpolarizing plate is also same as in Example 6.

Example 8

FIG. 25 shows a plan view of Example 8 of the present invention. ThisExample adopts a cross section structural figure of Example 1, and aliquid crystal alignment direction control electrode 15 encloses aperiphery of a transparent pixel electrode 8, which makes it difficultthat the transparent pixel electrode 8 is influenced by a potentialvariation of a video signal wiring 11, and hardly generates aperpendicular cross talk. One row of liquid crystal alignment directioncontrol electrode 15 exists in one pixel, and adjacent transparent pixelelectrodes 8 are connected to a thin film transistor element 16controlled by a different scan signal wiring 17, respectively. A drivingmethod of this Example is same as in Example 6. Many circular holes areformed in the transparent pixel electrode 8. As long as they are holes,polygonal forms may be of any kinds other than a circular form. Arotatory polarization liquid crystal display mode may be realizable byblending one of chiral material of left-handed rotation or right-handedrotation to an anisotropic liquid crystal having a negative dielectricconstant. In this case, a value of product of a liquid crystal cell gapd and a refractive index anisotropy Δn should just be in a range of0.30-0.60 micrometer. Molecules of anisotropic liquid crystal having anegative dielectric constant tilt aligning in a shape of a swirl, whileperforming a left slewing motion or a right slewing motion centering ona circular hole, can pass a light from a backlight from perpendicularlyarranged polarizing plates.

Example 9

FIG. 20 shows a plan view of active matrix substrate of Example 9 of thepresent invention. Both of contact button parts of contact buttons 30,33, and 36 of a scan signal wiring and contact buttons 38 and 39 of aliquid crystal alignment direction control electrode are gathered a inleft side of a display screen. FIG. 19 shows an expansion plan view ofthe contact button part.

FIG. 13 shows an expansion plan view of a contact button part in thecase where liquid crystal alignment direction control electrodes of tworows exist in one pixel. FIG. 13 shows an upper liquid crystal alignmentdirection control electrode contact button 31 of n row, a lower liquidcrystal alignment direction control electrode contact button 32 of nrow, an upper liquid crystal alignment direction control electrodecontact button 34 of (n+1) row, and a lower liquid crystal alignmentdirection control electrode contact button 35 of (n+1) row. One scansignal wiring is sandwiched from both of upper side and lower side byliquid crystal alignment direction control electrodes of different rows.Polarity switching of upper-side and lower-side liquid crystal alignmentdirection control electrodes is simultaneously performed based on atiming as shown in FIG. 33, and thereby a potential variation of thescan signal wiring may be controlled minimal, which suppressesgeneration of horizontal periodic unevenness in a display screen. AsFIG. 13 show, a short-circuit between contact buttons may be preventedby providing a distance between the contact buttons 30, 33, and 36 ofthe can signal wiring, and the contact buttons 31, 32, 34, and 35 of theliquid crystal alignment direction control electrode.

Example 10

FIG. 15 and FIG. 21 show a plan view of an active matrix substrate ofExample 10 of the present invention. Contact buttons 30, 33, and 36 of ascan signal wiring and contact buttons 38 and 39 of a liquid crystalalignment direction control electrode are separately divided into leftside and right side of a display screen, respectively. A driving methodof this Example may be methods as shown in FIG. 11 and FIG. 12, and maybe a method as shown in FIG. 33. In Example of the present invention,since a distance between contact buttons is expandable by adoptingarrangements shown in FIG. 15 and FIG. 21, a short-circuit betweencontact buttons can be prevented. Furthermore, usual scan signal wiringdrive IC in TN mode may be used, which enable cost reduction indevelopment and production.

Example 11

FIG. 26 and FIG. 27 show a plan view of an active matrix substrate ofExample 11 of the present invention. Contact buttons 30, 33, and 36 of ascan signal wiring and contact buttons 31, 32, 34, 35, 38, and 39 of aliquid crystal alignment direction control electrode are provided inboth of right and left ends of a display screen, which may solve easilya problem of delay of scan signal waveform, a largest problem whendriving a large-sized liquid crystal display.

In addition, FIG. 15, FIG. 20, FIG. 21, FIG. 26, and FIG. 27 show avideo signal wiring terminal area 40, a pixel circumference commonelectrode terminal area 41, and a protection network 42 for staticelectricity countermeasure.

Example 12

FIG. 34, FIG. 35, and FIG. 38 show a sectional view, a model view, and aplan view of Example 12 of the present invention. FIG. 51 and FIG. 52show a manufacturing process flow of a TFT (Thin Film Transistor) arraysubstrate of Example 12 of the present invention. FIG. 63 and FIG. 64show an expanded sectional view of the TFT array substrate.

Color filter substrate 1 has a flat transparent common electrode 4, andan active matrix substrate 13 is arranged in parallel countering thissubstrate 1. Although bumps 5 for controlling a motion direction of aliquid crystal are formed on a flat transparent common electrode 4 asshown in FIG. 1 in conventional liquid crystal panel in verticallyaligned mode, a liquid crystal panel in vertically aligned mode of thepresent invention does not require such bumps.

In the active matrix substrate 1, after formation of the scan signalwiring 17, an insulator film 12 and an amorphous silicone layer (nondoped layer) 65 and an n⁺ amorphous silicone layer 66 for ohmic contactsare deposited. A video signal wiring 11, a drain electrode, and a liquidcrystal alignment direction control electrode 15 are simultaneouslyformed in the same layer after formation of a thin film transistorelement part. A thin film transistor element, a video signal wiring 11,a drain electrode, and a liquid crystal alignment direction controlelectrode 15 are possible to be prepared in the same layersimultaneously, using a half-tone exposure technique currently disclosedin Japanese Patent Laid-Open No. 2000-066240. FIG. 64 shows a sectionalview of a thin film transistor element and an active matrix substrate ofExample 12 of the present invention using the half-tone exposure. Inaddition, FIGS. 63 and 64 show a scanning line terminal area 64.

As shown in FIG. 38, in Example 12 of the present invention, a number ofthin film transistor elements required in one pixel is only two. Atransparent pixel electrode 8 of n row and m column is connected with athin film transistor element 16 formed in a position where a scan signalwiring of n row 17 and a video signal wiring of m column 11 intersectwith each other, and a liquid crystal alignment direction controlelectrode 15 is connected with a thin film transistor element 49 formedin a position where a scan signal wiring of (n−1) row 17 and a videosignal wiring of (m+1) column 11 intersect with each other. Two kinds ofslits are formed in the transparent pixel electrode 8, and FIG. 99 andFIG. 100 show a cross section enlargement of the slits.

In a slit 9 of type in FIG. 99, when a voltage is impressed, verticallyaligned liquid crystal molecules 14 tilt in directions shown in FIG. 99.In a slit of a type in FIG. 100, a liquid crystal alignment directioncontrol electrode 15 is arranged via an insulator film on a lower layerof the slit. In a slit of a type in FIG. 100, when a voltage isimpressed, vertically aligned liquid crystal molecules 14 tilt indirections shown in FIG. 100. FIG. 41 and FIG. 42 show modified methodsof FIG. 99 and FIG. 100. FIG. 41 and FIG. 42 show an opening 59currently formed in a transparent pixel electrode on a liquid crystalalignment direction control electrode 15. In FIG. 100, the liquidcrystal alignment direction control electrode 15 has a larger size thanthat of a slit of the transparent pixel electrode 8, and overlaps eachother via an insulator film. An important point of the present inventionis a point that the transparent pixel electrode 8 and the liquid crystalalignment direction control electrodes 15 overlap one another via aninsulator film 12 to form a capacitance.

Molecules of anisotropic liquid crystal having a negative dielectricconstant 14 may be made to move in same directions as in FIG. 100 alsoin an electrode structure arrangement as shown in FIG. 101, in a planarstructure as shown in FIG. 93, a transparent pixel electrode 8 and aliquid crystal alignment direction control electrodes 15 do not overlapone another, and a capacitance formed by the transparent pixel electrode8 and the liquid crystal alignment direction control electrode 15 issmall, but problems will be caused if a drive system of the presentinvention is used.

As shown in FIG. 94 and FIG. 95, it is particularly important in a drivesystem of the present invention that a transparent pixel electrode 8 anda liquid crystal alignment direction control electrodes 15 overlap atleast in some area via an insulator film.

Example 13

FIG. 40 and FIG. 43 show a sectional view and a plan view of Example 13of the present invention. FIG. 53 and FIG. 54 show a manufacturingprocess flow of a TFT array substrate of Example 13 of the presentinvention. FIG. 61 and FIG. 62 show an expanded sectional view of theTFT array substrate.

A color filter substrate 1 has a flat transparent common electrode 4,and does not have bumps as in Example 12.

In an active matrix substrate 13, after a scan signal wiring 17 and aliquid crystal alignment direction control electrode 15 are first formedin the same layer simultaneously, an insulator film 12, an amorphoussilicone layer 65 (non doped layer), and n⁺ amorphous silicone layer 66for ohmic contacts are deposited. A video signal wiring 11 and a drainelectrode are simultaneously formed after formation of a thin filmtransistor element part.

A thin film transistor element, a video signal wiring 11, and a drainelectrode are possible to be prepared in the same layer simultaneously,using a half-tone exposure technique currently disclosed in JapanesePatent Laid-Open No. 2000-066240. FIG. 62 shows a sectional view of athin film transistor element and an active matrix substrate of Example13 of the present invention using the half-tone exposure.

As shown in FIG. 43, in Example 13 of the present invention, a number ofthin film transistor elements required in one pixel is only two. Atransparent pixel electrode 8 of n row and m column is connected with athin film transistor element 16 formed in a position where a scan signalwiring of n row 17 and a video signal wiring of m column 11 intersectwith each other, and a liquid crystal alignment direction controlelectrode 15 is connected with a thin film transistor element 49 formedin a position where a scan signal wiring of (n−1) row 17 and a videosignal wiring of (m+1) column 11 intersect with each other. In Example12, since a drain electrode of this thin film transistor element and aliquid crystal alignment direction control electrode 15 aresimultaneously formed in the same layer, these are connectedautomatically, but in Example 13, since a drain electrode of this thinfilm transistor element and a liquid crystal alignment direction controlelectrode 15 are not formed in the same layer, two contact holes 61 and62 must be provided in order to electrically connect these twoelectrodes. Although existence of two thin film transistor elements 16and 49 and one contact hole 56 was enough for Example 12, Example 13requires two thin film transistor elements 16 and 49 and three contactholes 56, 61, and 62, as shown in FIG. 43.

Example 14

FIG. 34, FIG. 36, and FIG. 39 show a sectional view, a model view, and aplan view of Example 14 of the present invention. FIG. 55 and FIG. 56show a manufacturing process flow of a TFT array substrate of Example 14of the present invention.

FIG. 67 and FIG. 68 show an expanded sectional view of the TFT arraysubstrate.

A color filter substrate 1 has a flat transparent common electrode 4,and does not have bumps as in Example 12.

In an active matrix substrate 13, after a scan signal wiring 17 and acommon electrode 48 in an active matrix side are first formed in thesame layer simultaneously, an insulator film 12, an amorphous siliconelayer 65 (non doped layer), and n⁺ amorphous silicone layer 66 for ohmiccontacts are deposited. A video signal wiring 11 and a drain electrodeare simultaneously formed after formation of a thin film transistorelement part.

A thin film transistor element, a video signal wiring, a drainelectrode, and a liquid crystal alignment direction control electrodeare possible to be prepared in the same layer simultaneously, using ahalf-tone exposure technique currently disclosed in Japanese PatentLaid-Open No. 2000-066240. FIG. 68 shows a sectional view of a thin filmtransistor element and an active matrix substrate of Example 14 of thepresent invention using the half-tone exposure.

As shown in FIG. 39, in Example 14 of the present invention, a number ofthin film transistor elements required in one pixel is only two. Atransparent pixel electrode 8 of n row and m column is connected with athin film transistor element 16 formed in a position where a scan signalwiring of n row 17 and a video signal wiring of m column 11 intersectwith each other, and a liquid crystal alignment direction controlelectrode 15 is connected with a thin film transistor element 50 formedon a scan signal wiring top 17 of (n−1) row. Although a structure oftransparent pixel electrode 8 may also have forms as in Example 12 andExample 13, in FIG. 39, slits 9 formed in a transparent pixel electrode8 are arranged horizontally and vertically to an extending direction ofa scan signal wiring 17, and slits forming a group with the liquidcrystal alignment direction control electrode 15 are arranged so as tomake an angle of ±45 degrees to an extending direction of the scanningline. Since a source electrode 69 of a thin film transistor element 50formed on the scan signal wiring 17 of (n−1) row and a common electrode48 of n row are not formed in the same layer in case of Example 14, twocontact holes must be formed in order to electrically connect these twoelectrodes. Accordingly, like Example 13, Example 14 requires two thinfilm transistor elements 16 and 50 and three contact holes 56, 57, and58, as shown in FIG. 39.

Example 15

FIG. 40 and FIG. 96 show a sectional view and a plan view of Example 15of the present invention. FIG. 57 and FIG. 58 show a manufacturingprocess flow of a TFT array substrate of Example 15 of the presentinvention. FIG. 65 and FIG. 66 show an expanded sectional view of theTFT array substrate. A color filter substrate 1 has a flat transparentcommon electrode 4, and does not have bumps as in Example 12.

In an active matrix substrate 13, after a scan signal wiring 17, acommon electrode 48, and a liquid crystal alignment direction controlelectrode 15 are first formed in the same layer simultaneously, aninsulator film 12, an amorphous silicone layer (non doped layer) 65, andan n⁺ amorphous silicone layer 66 for ohmic contacts are deposited. Avideo signal wiring 11 and a drain electrode are simultaneously formedafter formation of a thin film transistor element part. A thin filmtransistor element, a video signal wiring 11, and a drain electrode arepossible to be prepared in the same layer simultaneously, using ahalf-tone exposure technique currently disclosed in Japanese PatentLaid-Open No. 2000-066240. FIG. 66 shows a sectional view of a thin filmtransistor element and an active matrix substrate of Example 14 of thepresent invention using the half-tone exposure.

As shown in FIG. 96, in Example 15 of the present invention, a number ofthin film transistor elements required in one pixel is only two. Atransparent pixel electrode 8 of n row and m column is connected with athin film transistor element 16 formed in a position where a scan signalwiring of n row 17 and a video signal wiring of m column 11 intersectwith each other, and a liquid crystal alignment direction controlelectrode 15 is connected with a thin film transistor element 50 formedon a scan signal wiring 17 top of (n−1) row. In Example 15, in order toelectrically connect a source electrode 69 of the thin film transistorelement formed on the scan signal wiring of (n−1) row 17, and a drainelectrode 70 with a common electrode 48 and the liquid crystal alignmentdirection control electrode 15, respectively, contact holes 57, 58, 71,and 72, respectively, must be provided. Accordingly, Example 15 requirestwo thin film transistor elements 16 and 50 and five contact holes 56,57, 58, 71, and 72 as shown in FIG. 96.

Example 16

FIG. 37 shows a timing chart about drive waveform that is Example 16 ofthe present invention. This is a drive waveform for driving a verticallyaligned mode liquid crystal display described in Examples 12, 13, 14,and 15. Here may be given an important aspect of the present inventionthat:

a scan signal waveform of a scan signal wiring of (n−1) row (addresssignal width) 52 and a signal waveform of a scan signal wiring of n row(address signal width 55 have a time width of at least no less thantwice of a horizontal period, and mutually overlap by a time width noless than one horizontal period; and a polarity of a video signalvoltage of a video signal wiring of m column and a polarity of a videosignal voltage of a video signal wiring of (m+1) column have a polaritydifferent from each other and have polarities mutually reversed everyhorizontal period.

FIG. 37 shows a common electrode potential 51, a video signal wiring ofm column signal waveform 53, and a video signal wiring of (m+1) columnsignal waveform 54.

When a drive system of the present invention is used, charging may beenabled to a capacitance C2 of a circuit model figure (capacitance C2 isa capacitance formed when a transparent pixel electrode and a liquidcrystal alignment direction control electrodes mutually overlap via aninsulator film), when a signal waveform of a scan signal wiring of (n−1)row and a signal waveform of a scan signal wiring of n row mutuallyoverlap, as shown in FIG. 47, FIG. 48, FIG. 49, and FIG. 50. Here, FIG.48 shows a potential of a position shown by A and B in a circuit modelfigure of FIG. 47, and FIG. 50 shows a potential of a position shown byA and B in a circuit model figure of FIG. 49.

In FIG. 47 and FIG. 48 a liquid crystal alignment direction controlelectrode is connected with a thin film transistor element formed in aposition where a video signal wiring of (m+1) column intersects a scansignal wiring of (n−1) row, a transparent pixel electrode is connectedwith a thin film transistor element formed in a position where a scansignal wiring of n row and a video signal wiring of m column intersectwith each other. When both of scanning lines of (n−1) row and n row areaddressed in case of a video signal wiring of m column having +7 V and avideo signal wiring of (m+1) column having −7 V, the above-mentioned twothin film transistor elements operate, and a capacitance C2 is chargedand potentials of A and B obtain +7 V and −7 V, respectively. After thescanning line of (n−1) row is closed, when a polarity of a voltage ofthe video signal wiring of m column is changed to −7 V from +7 V and apolarity of a voltage of the video signal wiring of (m+1) column ischanged to +7 V from −7 V, since a thin film transistor element of n rowis operating, a potential of A of capacitance C2 varies to −7 V from +7V. Since a thin film transistor element of (n−1) row is not operating atthis time, a potential of B of capacitance C2 varies to −21 V from −7 V.Next, when the scanning line of n row is closed, in potential of pixelof n row m column capacitance C2, A is fixed to −7 V and B to −21 V.

Same operation is performed after one perpendicular period, and since apolarity of the signal voltage of video signal wiring of m column and apolarity of the signal voltage of video signal wiring of (m+1) columnare reversed, in potential of capacitance C2 after one perpendicularperiod, A is fixed to +7V, and B to +21V. Such potential relationshipoccurs, thereby a distribution of equipotential line as shown in figureare realized, and a motion direction of liquid crystal molecules may bedetermined. Since a large electric field is generated between thetransparent pixel electrode and the liquid crystal alignment directioncontrol electrode, large motion speed of liquid crystal molecule may berealized.

In FIG. 49 and FIG. 50, a liquid crystal alignment direction controlelectrode is connected with a thin film transistor element formed on ascan signal wiring of (n−1) row, and a source electrode of this thinfilm transistor element is connected with a common electrode of n rows.A transparent pixel electrode is connected with a thin film transistorelement formed in a position where a scan signal wiring of n row and avideo signal wiring of m column intersect with each other. When both ofscanning lines of (n−1) row and n row are addressed in case of a videosignal wiring of m column having +7 V and a video signal wiring of (m+1)column having −7 V, the above-mentioned two thin film transistorelements operate, and a capacitance C2 is charged and potentials of Aand B obtain +7 V and 0 V, respectively. After the scanning line of(n−1) row is closed, when a polarity of a voltage of the video signalwiring of m column is changed to −7V from +7V and a polarity of avoltage of the video signal wiring of (m+1) column is changed to +7Vfrom −7V, since a thin film transistor element of n row is operating, apotential of A of capacitance C2 varies to −7V from +7V. Since a thinfilm transistor element of (n−1) row is not operating at this time, apotential of B of capacitance C2 varies to −14V from 0 V. Next, when thescanning line of n row is closed, in potential of pixel of n row mcolumn capacitance C2, A is fixed to −7 V and B to −21 V.

Same operation is performed after one perpendicular period, and since apolarity of the signal voltage of video signal wiring of m column and apolarity of the signal voltage of video signal wiring of (m+1) columnare reversed, in potential of capacitance C2 after one perpendicularperiod, A is fixed to +7 V, and B to +14 V. Such potential relationshipsoccur, thereby a distribution of equipotential line as shown in figuremay be realized, and a motion direction of liquid crystal molecules maybe determined.

Example 17

FIG. 44, FIG. 59, FIG. 60, FIG. 45, and FIG. 46 show a plan view and asectional view of Example 17 of the present invention. FIG. 53 and FIG.54 show a manufacturing process flow of a TFT array substrate of Example17 of the present invention. FIG. 61 and FIG. 62 show an expandedsectional view of the TFT array substrate.

A color filter substrate 1 has a flat transparent common electrode 4,and does not have bumps as in Example 12. A connection method of aliquid crystal alignment direction control electrode 15 and a thin filmtransistor element is completely same as in Example 13.

In Example 17, slits formed in a transparent pixel electrode 8 hasdifferent forms from that in Example 13, they comprise a form arrangedat +45 degrees to a direction of the scan signal wirings, a formarranged horizontally or vertically, or a form having circular ofpolygonal openings 63, as shown in FIG. 44, FIG. 59, and FIG. 60. Aliquid crystal alignment direction control electrode 15 enclosesperiphery of a transparent pixel electrode 8, as shown in FIG. 44, FIG.59, and FIG. 60, and the liquid crystal alignment direction controlelectrode 15 forming a group with a slit is arranged horizontally orvertically to a direction of a scan signal wiring 17.

Example 18

FIG. 69, FIG. 70, FIG. 71, FIG. 72, FIG. 73, and FIG. 74; and FIG. 77,FIG. 78, FIG. 79, FIG. 80, FIG. 83, FIG. 84, FIG. 85, FIG. 86; and FIG.91 and FIG. 92 show a circuit model figure of Example 18 of the presentinvention, and a plan view and sectional view of a thin film transistor.

Here, C1 is a capacitance formed with a transparent pixel electrode 8and a flat transparent common electrode 4 in a CF (color filter)substrate side; C2 is a capacitance formed with the transparent pixelelectrode 8 and a liquid crystal alignment direction control electrode15; C3 is a capacitance formed with the transparent pixel electrode 8and a scanning line; C4 is a capacitance formed with an intermediateelectrode 67 of a double thin film transistor, and the transparent pixelelectrode 8; and C5 is a capacitance formed with the transparent pixelelectrode 8, and a common electrode 48 in an active matrix substrateside.

As already described in Example 16 of the present invention, when adrive system of the present invention is used, since a voltage impressedbetween electrodes of a video signal wiring of (m+1) column connectedwith a thin film transistor element formed on a scan signal wiring of(n−1) row and a liquid crystal alignment direction control electrodereaches about 28 V at the maximum, a problem occurs that a leakagecurrent between these two electrodes increases. Accordingly, in Example18 of the present invention, a double transistor structure is adopted asa structure of a thin film transistor element that is formed on a scansignal wiring 17 of (n−1) row, and is connected with a liquid crystalalignment direction control electrode 15. As shown in FIG. 91 and FIG.92, the double transistor structure has a channel length longer thanusual single transistor element, and even if a high voltage is impressedbetween a source electrode and a drain electrode, it can suppressincrease in a leakage current. When not using a double transistorstructure, it is also effective for reduction of a leakage current tolengthen a channel length of a transistor. As shown in FIG. 61 or FIG.65, a channel length (L₂) of a thin film transistor element connectedwith a liquid crystal alignment direction control electrode is setlarger than a channel length (L₁) of a thin film transistor elementconnected with a transparent pixel electrode, and thereby a leakagecurrent may be reduced.

As a method for reducing a leakage current between a source electrodeand a drain electrode, offset transistor structure as shown in FIG. 88,FIG. 89, and FIG. 90 may also be conceivable. In this case, a thin filmtransistor structure of a planar structure as shown in FIG. 87 isadopted. Here, notation F in FIG. 88, FIG. 89, and FIG. 90 shows amountof offset of an offset thin film transistor element. Moreover, anetching stopper layer 68 is shown in FIG. 90.

Example 19

FIG. 41, FIG. 42, FIG. 94, and FIG. 95 show a plan view of Example 19 ofthe present invention. This Example relates to a form of a transparentpixel electrode 8 and a liquid crystal alignment direction controlelectrode 15 used for Examples 12, 13, 14, 15, and 17. Molecules ofanisotropic liquid crystal having a negative dielectric constant 14 hasa property to arrange a direction of extended shaft of liquid crystalmolecules 14 in a direction extending lengthwise of a wedge of atransparent pixel electrode 8 when a voltage is impressed, generation ofdisclination may be suppressed by adopting a form of Example 19 of thepresent invention.

Generation of disclination has a tendency for a transmittance of aliquid crystal panel and also for a speed of response to be reduced. Aseed of response and a transmittance may be improved by adopting a formof the present invention.

Besides, as structures of a thin film transistor element of the presentinvention, two kinds of structures as FIG. 97 and FIG. 98 show may beconceivable. A type shown in FIG. 97 has a structure arrangement that:in a pixel of n row m column, a thin film transistor element is formedin a position where a scan signal wiring of (n−1) row and a video signalwiring of (m+1) column intersect with each other, a video signal wiringof (m+1) column, and a liquid crystal alignment direction controlelectrode used for the pixel of n row m column are connected via thisthin film transistor element; and a thin film transistor element isformed in a position where a scan signal wiring of n row and a videosignal wiring of m column intersect with each other, and the videosignal wiring of m column, and a transparent pixel electrode used forthe pixel of n row m column are connected via this thin film transistorelement.

On the contrary, B type shown in FIG. 98 has a structure arrangementthat: in a pixel of n row m column, a video signal wiring of m columnand a liquid crystal alignment direction control electrode used for thepixel of n row m column are connected via a thin film transistor elementin a position where a scan signal wiring of (n−1) row and a video signalwiring of m column intersect with each other; and a video signal wiringof (m+1) column and a transparent pixel electrode used for the pixel ofn row m column are connected via a thin film transistor element in aposition where a scan signal wiring of n row and a video signal wiringof (m+1) column intersect with each other. The present inventionincludes both of A type structure and B type structure.

Use of the present invention does not require use of color filtersubstrates with bumps or slits that have been used for conventionalmulti-domain vertically aligned mode liquid crystal displays, butenables reduction of cost.

In addition, it may also cancel simultaneously display unevennessinduced by variation accompanying bumps or processing of slits, andextremely improves yield.

Furthermore, it suppresses problems of unevenness, or residual image(image burn-in) caused by diffusion of impurities in pigments of a colorfilter, or impurities in bumps from crevices of bumps or slits intoliquid crystals, and thereby realizes extremely reliable verticallyaligned mode liquid crystal displays.

Since possibility of reworking may easily be realized with oxygen plasmatreatment irrespective of defects generation in a polyimide alignmentlayer application process, reduction of reworking costs may be realized.

Use of electrode structures, structure arrangements, and driving methodsof the present invention may enable production of active matrixsubstrates having a large aperture ratio, and may provide bright viewingdisplays. Furthermore, since it may improve a speed of response ofliquid crystal molecules, very large-sized liquid crystal TVs respondinganimated pictures may be realized. In addition, it may realize a uniformblack display with little light leakage in a dark room as compared withconventional vertically aligned mode liquid crystal displays usingbumps.

1. A method for driving a color active matrix type vertically alignedmode liquid crystal display having a transparent pixel electrode inwhich two or more long and slender slits are formed, an active matrixsubstrate having a liquid crystal alignment direction control electrodein a lower layer of the slits of the transparent pixel electrodecurrently formed via an insulator film, a color filter substrate facingthe active matrix substrate, and an electrode structure for each pixelof the active matrix substrate in which (i) a transparent flat commonelectrode is used in the color filter substrate side, and for thetransparent pixel electrodes facing the transparent flat commonelectrode in the active matrix substrate side, patterns (no transparentelectrode in a slit part) having a shape of a long and slender slit areformed, and (ii) a transparent flat common electrode is used in thecolor filter substrate side, and for the transparent pixel electrodefacing the transparent flat common electrode in the active matrixsubstrate side, patterns having a shape of a long and slender slit areformed, and two rows of liquid crystal alignment direction controlelectrodes that are mutually separated and set as potentials differentfrom each other exist in a lower layer of the transparent pixelelectrode via the insulated film, either of the liquid crystal alignmentdirection control electrodes has almost the same shape as a shape of apattern of the shape of long and slender slits, and a larger dimensionthan a dimension of the slits, and two rows of the liquid crystalalignment direction control electrodes mutually separated are arrangedin a direction of a scan signal wiring in a lower layer of the long andslender slits that are formed, mutually exchanged in an every fixedpixel cycle, in the transparent pixel electrode; said driving methodcomprising the following steps of: setting a potential of the liquidcrystal alignment direction control electrode currently placed in alower layer of the slit of the transparent pixel electrode lower than apotential of the transparent pixel electrode when a potential of thetransparent pixel electrode separated for every pixel of the activematrix substrate side is lower than a potential of the facing flatcommon electrode on the color filter substrate side; setting a potentialof the liquid crystal alignment direction control electrode placed in alower layer of the slit of the transparent pixel electrode higher than apotential of the transparent pixel electrode when a potential of thetransparent pixel electrode is higher than a potential of the facingflat common electrode of the color filter substrate side; settingpotentials of the liquid crystal alignment direction control electrodesarranged in the vicinity of both sides of the scan signal wiring aspolar potentials different from each other; and reversing polarities ofthe potential of the transparent pixel electrode, and each of thepotentials of the two rows of the liquid crystal alignment directioncontrol electrodes mutually separated in one pixel to a polarity of apotential of the flat common electrode on the color filter substrateside every vertical scanning period.